Process for dyeing animal fibers with complex chromium compounds of azo dyestuffs



Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE PROCESS FOR DYEING ANIMAL FIBERS WITH COMPLEX CHROMIUM COMPOUNDS 0F AZO DYESTUFFS Switzerland No Drawing. Application February 18, 1937, Se-

rial No. 126,520. In Switzerland February 26,

4 Claims.

It has been found that animal fibers, for example Wool and natural silk, can be dyed with the complex chromium compounds of the amdyestufis of the general formula OH OH wherein R1 represents a naphthalene radical free of nitro groups and R2 represents a naphthalene radical containing no substituents besides the hydroxyl group, and wherein further the two hydroxyl groups stand in ortho-position to the axebridge, by adding the dyestuffs in portions to the dye-bath.

Complex chromium compounds of the azo-dyestuffs of the above general formula are for example the complex chromium compounds of the azo-dyestuffs from diazotized 1 amino 2-hydroxynaphthalene-4-sulfonic acid, from diazotized Z-amino-1-hydroxynaphthalene-4-sulfonic acid, as well as from diazotized chloroor bromo- 1-amino-2-hydroxynaphthalene 4 sulfonic acid and 1- or 2-hydroxynaphthalene. These complex chromium compounds may be produced according to the most difierent known processes. Apart from these dyestuffs there may also be used other dyestuffs, particularly such dyestuffs which are suitable for shading navy blues.

The dyestuff may be added to the dye-bath in two or more portions and at shorter or longer intervals; in many cases it is of particular advantage if the aqueous solution of the dyestuff is allowed to flow into the dye-bath during the dyeing, this flow being extended over a considerable portion of the duration of the dyeing.

In some cases it is advantageous to add to the bath a wetting agent, a dispersing agent or an emulsifying agent.

The conditions usual in dyeing animal fibres with chromium compounds of azo-dyestuffs may be observed; accordingly the animal fibers may be dyed in baths containing organic (aliphatic, aromatic or hydroaromatic) acids together with mineral acids, such as sulphuric acid, or merely in presence of sulphuric acid, in a proportion of about 5-10 per cent. of the goods to be dyed; in some cases it is also of advantage to add the acid also in portions and to begin the dyeing at about -90 C.

The process leads to uniform deep navy blue tints fast to rubbing, against which vegetable fibers, such as cotton and also artificial silk from regenerated cellulose or acetate artificial silk, can be reserved, whereas by dyeing with the same dyestuffs according to the customary processes there are obtained dyeings which are not uniform and are not fast to rubbing and are insufilciently reserved.

The following examples illustrate the invention, the parts being by weight.

Example 1 100 parts of woollen piece goods are entered into a dye-bath having a temperature of 90 C. and composed of 3000 parts of water, 4 parts of concentrated sulphuric acid and 2 parts of the chromium compound of the azo-dyestufif of the formula OaH Example 2 A dye-bath is prepared with 3000 parts of water and 4 parts of concentrated sulphuric acid, and at a temperature of C. parts of wool are entered, moved in the bath for a short time until the material is well penetrated, and then whilst the liquor is kept in motion a solution of 3.6 parts of the chromiferous azo-dyestufi from diazotized l-amino 2 oxynaphthalene 4 sulphonic acid and 2-oxynaphthalene in 50 parts of water is run in at 90-95 C. in the course of hour. After an hour 4 parts of concentrated sulphuric acid are added and the bath is maintained boiling for 1-1 hours longer; then the material is washed and dried. It is dyed deep navy blue shades of excellent properties of fastness.

Example 3 100 parts of woollen piece goods are wetted in a bath at 90 C. consisting of 2500 parts of water and 8 parts of concentrated sulphuric acid. Then 'a solution of 4 parts of the chromium compound of the azo-dyestuff of the formula Example 4 100 parts of woollen piece goods are entered into a dye-bath of 85-90 C. composed of 2500 parts of water and 5.8 parts of formic acid of 85 per cent. strength. In the course of -30 minutes there is allowed to run in a solution of 4 parts of the chromium compound of the azo-dyestuff from diazotized l-amino 2 oxynaphthalene 4 sulphonic acid and 2-oxynaphthalene in parts of water. The bath is boiled for /2 hour, 6 parts of concentrated sulphuric acid are cautiously added and boiling is continued for l-1 hours longer; the material is then Washed and dried. There are obtained navy blue shades of excellent fastness properties.

Example 5 A dye-bath of C. is prepared from 3000 parts of water and 8 parts of concentrated sulphuric acid and parts or" loose wool are entered and moved in the bath for a short time until thoroughly penetrated. Then in the course of Ao hour the dyestuff solution of 5 per cent. strength, consisting of 3.2 parts of the chromiferous azo-dyestuff from diazotized l-amino-Z- oxynaphthalene-4-sulphcnic acid and 2-oxynaphthalene and 0.6 part of the chromiferous azo-dyestuff of the formula from diazotized 1-methyl-3-amino-4-oxybenzenefi-sulphonic acid and 2-oxynaphthalene, is run in whilst the liquor is kept in motion. Simultaneously, the bath is brought slowly to the boil and kept boiling for 1-l hours longer; the material is then washed and dried. There are obtained reddish-navy blue shades of very good fastness properties.

Example 6 Into a dye-bath heated to 90 C. and consisting of 2400 parts of water, 8 parts of sulphuric acid of 100 per cent. strength. and 8 parts crystallized sodium sulphate, 100 parts of woollen piece goods are entered and while handling the goods a dyestuff solution of 3.6 parts of the chromium compound of the azo-dyestuif from diazotized 1- amino-2-oxynaphthalene-4-sulphonic acid and 2-oxynaphthalene made as described in Example 1 of Patent No. 1,480,640 in about 200 parts of water is allowed to run into the bath in the course of %-1 hour.

The bath. is then boiled, if desired with addition of water to make good that evaporated, for 1-1 hours. The goods are then thoroughly Washed with water and dried. They are dyed uniform navy blue of excellent properties of fastness.

What we claim is:-

1. Process for dyeing animal fibers with complex chromium compounds of azo-dyestufis of the general formula wherein R2 represents a naphthalene radical containing no substituent besides the hydroxyl group, and wherein the hydroxyl group of the naphthalene radical R2 stands in ortho-positio-n to the azo-bridge, consisting in dyeing animal fibers in a dye-bath to which the complex chromium compounds of the azo-dyestufis are added in portions during the dyeing process.

3. Process for dyeing animal fibers with the complex chromium compound of the azo dyestufi of the formula --OH HO I S 03H consisting in dyeing animal fibers in a dye-bath to which the complex chromium compound of the azo-dyestuff is added in portions during the dyeing process.

4. Process for dyeing animal fibers with the complex chromium compound of the azo-dyestufi consisting in dyeing animal fibers in a dye-bath of the formula. and allowing an aqueous solution of the dyestufi to run into the dye-bath during the dyeing operation, this running in being extended over 2. H0 considerable period of the duration of the dyeing. 5

FRITZ STRAUB.

| HERMANN SCHNEIDER. S 0511 

